1、支气管哮喘(Bronchial-Asthma)精品课件Outlinen Burden of Asthma n Definition of Asthman Etiology and Mechanismn Diagnosis and Classificationn Asthma Medicationsn Asthma management and PreventionBurden of AsthmaHealth care expenditures very highDeveloped economies might expect to spend 1-2 percent of total heal
2、th care expenditures on asthma.Developing economies likely to face increased demandPoorly controlled asthma is expensive;investment in prevention medication likely to yield cost savings in emergency careAsthma Prevalence and MortalityEpidemiology of AsthmaProportion of population with asthma(%)Case
3、fatality rate per 100,000 asthmaticsDefinition of AsthmaA chronic inflammatory disorder of the airwaysMany cells and cellular elements play a roleChronic inflammation is associated with airway hyperresponsiveness that leads to recurrent episodes of wheezing,breathlessness,chest tightness,and coughin
4、gWidespread,variable,and often reversible airflow limitationMechanismsAsthma InflammationAsthma InflammationRisk Factors for AsthmaHost factors:predispose individuals to,or protect them from,developing asthmaEnvironmental factors:influence susceptibility to development of asthma in predisposed indiv
5、iduals,precipitate asthma exacerbations,and/or cause symptoms to persistFactors that Influence Asthma Development and ExpressionHost FactorsGenetic -Atopy -Airway hyperresponsiveness GenderObesityEnvironmental Factorsn Indoor allergensn Outdoor allergensn Occupational sensitizersn Tobacco smoken Air
6、 pollutionn Respiratory Infectionsn DietMajor Indoor Asthma TriggersIs it Asthma?Recurrent episodes of wheezingTroublesome cough at nightCough or wheeze after exerciseCough,wheeze or chest tightness after exposure to airborne allergens or pollutantsColds“go to the chest”or take more than 10 days to
7、clearAsthma Diagnosis History and patterns of symptoms-Episodic symptoms after an incidental allergen exposure,seasonal variability of symptoms;-Positive family history of asthma and atopic disease;-Symptoms improved by appropriate asthma treatment;Physical examination-May be normal;-The most usual
8、abnormal physical finding is wheezing on auscultation;Asthma DiagnosisMeasurements of lung function -Spirometry -Peak expiratory flowMeasurement of airway responsiveness Measurements of allergic status to identify risk factorsExtra measures may be required to diagnose asthma in children 5 years and
9、younger and the elderlyTypical Spirometric(FEVTypical Spirometric(FEV1 1)TracingsTracingsTime(sec)FEV1VolumeNote:Each FEV1 curve represents the highest of three repeat measurementsMeasuring Variability of Peak Expiratory FlowMeasuring Airway ResponsivenessEtiologic Diagnosis Identify environmental f
10、actors Allergen challenge testSkin prick testSpecific IgEDifferential DiagnosisOther forms of obstructive lung disease,particularly COPD Non-respiratory causes of symptoms(e.g.,left ventricular failure)Non-obstructive forms of lung disease(e.g.,diffuse parenchymal lung disease)Upper airway obstructi
11、on and inhaled foreign bodiesController MedicationsnInhaled glucocorticosteroidsnLeukotriene modifiersnLong-acting inhaled 2-agonistsnSystemic glucocorticosteroids nTheophyllinenCromonesnLong-acting oral 2-agonistsnAnti-IgEnSystemic glucocorticosteroidsEstimate Comparative Daily Dosages for Inhaled
12、Glucocorticosteroids by AgeDrug Low Daily Dose(g)Medium Daily Dose(g)High Daily Dose(g)5 y Age 5 y Age 5 y Age 12yrs with mild persistent asthma.Further study neededPharmacologic TherapyQuick relief medications Short acting beta2-agonists-relief of acute symptoms Anticholinergics-may provide additiv
13、e benefit to beta2 drugs in severe exacerbation.May be alternative to beta2-agonists Systemic steroids-moderate-to-severe persistent asthma in acute exacerbations or to prevent recurrence of exacerbationsPharmacologic TherapyTreatment/Long Term ControlCorticosteroids Most potent and effective Reduct
14、ion in symptoms,improvement in PEF and spirometry,diminished airway hyperresponsiveness,prevention of exacerbations,possible prevention of airway wall remodeling Suppresses:cytosine production,airway eosinophilic recruitment,chemical mediators Long-acting beta-2 agonists Relax airway smooth muscle D
15、uration of action 12 hrs Not used in acute exacerbations Adjunct to anti-inflammatory tx for long-term symptom control especially nocturnal symptomsTreatment/Long Term ControlLeukotriene modifiers Leukotrienes are potent biochemical mediators released from mast cells,eosinophils,and basophils that:c
16、ontract bronchial smooth muscle increase vascular permeability increase mucus secretions attract&activate inflammatory cells in airwaysTreatment/Long Term ControlAsthma Treatment/Quick ReliefShort-acting beta2 agonists Relax airway smooth muscle and increase in airflow in 1 canister/mo indicates ina
17、dequate control and indicates need to intensify anti-inflammatory tx Regularly scheduled use NOT recommendedAnticholinergics Cholinergic innervation important in regulation of airway smooth muscle tone Ipratropium bromide(quaternary derivative of atropine without its side effects)Additive benefit wi
18、th inhaled beta 2-agonists in severe asthma exacerbations Effectiveness in long-term management not demonstratedAsthma Treatment/Quick ReliefSystemic steroids speed resolution of airflow obstruction reduce rate of relapseMedications to reduce oral steroid dependence Troleandomycin,cyclosporin,gold,m
19、ethotrexate,IV immunoglobulin,dapsone,hydroxychloroquine Asthma Treatment/Quick ReliefAsthma Medication EquipmentMethods of Delivery Medications may be given by:-Metered Dose Inhaler(MDI)-Dry Powdered Inhaler(DPI)-Nebulizer-OrallyImportant to review technique for all delivery methodsClinical Control
20、 of Asthma No(or minimal)*daytime symptoms No limitations of activity No nocturnal symptoms No(or minimal)need for rescue medication Normal lung function No exacerbations_*Minimal=twice or less per weekLevels of Asthma ControlGoals of Long-term ManagementnAchieve and maintain control of symptomsnMai
21、ntain normal activity levels,including exercisenMaintain pulmonary function as close to normal levels as possiblenPrevent asthma exacerbationsnAvoid adverse effects from asthma medicationsnPrevent asthma mortalitycontrolledpartly controlleduncontrolledexacerbationmaintain and find lowest controlling
22、 stepconsider stepping up to gain controlstep up until controlledtreat as exacerbationTREATMENT STEPSREDUCEINCREASESTEP1STEP2STEP3STEP4STEP5REDUCEINCREASEExacerbations of asthma are episodes of progressive increase in shortness of breath,cough,wheezing,or chest tightnessExacerbations are characteriz
23、ed by decreases in expiratory airflow that can be quantified and monitored by measurement of lung function(FEV1 or PEF)Severe exacerbations are potentially life-threatening and treatment requires close supervisionManage Asthma ExacerbationsPrimary therapies for exacerbations:Repetitive administratio
24、n of rapid-acting inhaled 2-agonist Early introduction of systemic glucocorticosteroids Oxygen supplementationClosely monitor response to treatment with serialmeasures of lung functionManage Asthma ExacerbationsAllergen-specific ImmunotherapynGreatest benefit of specific immunotherapy using allergen
25、 extracts has been obtained in the treatment of allergic rhinitisnThe role of specific immunotherapy in asthma is limitednSpecific immunotherapy should be considered only after strict environmental avoidance and pharmacologic intervention,including inhaled glucocorticosteroids,have failed to control
26、 asthmanPerform only by trained physicianSpecial ConsiderationsSpecial considerations are required tomanage asthma in relation to:PregnancySurgeryRhinitis,sinusitis,and nasal polypsOccupational asthmaRespiratory infectionsGastroesophageal refluxAspirin-induced asthmaAnaphylaxis and Asthma1.Develop P
27、atient/Doctor Partnership2.Identify and Reduce Exposure to Risk Factors3.Assess,Treat and Monitor Asthma4.Manage Asthma Exacerbations5.Special ConsiderationsAsthma Management and PreventionProgram:Five ComponentsRevised 2006nAsthma can be effectively controlled in most patients by intervening to sup
28、press and reverse inflammation as well as treating bronchoconstriction and related symptomsnAlthough there is no cure for asthma,appropriate management that includes a partnership between the physician and the patient/family most often results in the achievement of controlAsthma Management and Preve
29、ntion Program:SummaryA stepwise approach to pharmacologic therapy is recommended.The aim is to accomplish the goals of therapy with the least possible medicationThe availability of varying forms of treatment,cultural preferences,and differing health care systems need to be considered Asthma Management and Prevention Program:Summary
